The present invention relates to a steel laminate gasket for an internal combustion engine to securely seal around cylinder holes and through holes.
An internal combustion engine is provided with a plurality of cylinder holes and other holes, such as holes for bolts, water, oil and push rods. When an engine is actuated, high pressure and high temperature are applied to the cylinder holes due to combustion of a fuel, while relatively low pressure and low temperature are applied to the other holes.
In order to properly seal between two engine blocks, such as a cylinder head and a cylinder block, of an engine, a gasket is situated between the two engine blocks and is tightened so that areas around the cylinder holes as well as the other holes are securely sealed. However, since the sealing conditions around the cylinder holes and other holes are different as explained above, it is not easy to securely seal around all the holes.
It has been known that beads are formed around the cylinder holes and other holes to securely seal around the holes. However, in case the beads are simply formed, sealing can not be perfectly made. Namely, while an engine is actuated, leakage may happen around the cylinder holes and other holes.
In some cases, seal rings may be separately attached around holes for water and oil. However, since the seal rings are separately prepared and installed in the gasket, it requires additional cost. Therefore, this method is not practical.
In U.S. Pat. No. 4,799,695, a metal laminate gasket is formed of an upper plate 1, and a lower plate 2 with a bead 3, as shown in FIG. 9 of the drawings filed herewith. An end of the upper plate 1 is folded and located under the lower plate 2 to form a flange 4. When this gasket is tightened between a cylinder head and a cylinder block, since an area on the flange 4 is formed of three plates and the rest of the portion is formed of two plates though the lower plate 2 has the bead 3, the cylinder head inclines relative to the cylinder block. Therefore, this structure is not practical.
Accordingly, an object of the present invention is to provide a steel laminate gasket which can seal properly around all kinds of holes in an engine.
Another object of the invention is to provide a steel laminate gasket as stated above, in which an area around a cylinder hole can be sealed strongly for a relatively wide width.
A further object of the invention is to provide a steel laminate gasket as stated above, in which sealing pressure around holes can be easily changed.
Further objects and advantages of the invention will be apparent from the following description of the invention.